In general, chronic skin inflammation is a major cause of wrinkles since it reduces elasticity of skin. Once inflammation occurs in skin, the inflammatory site often turns dark brown because of increased pigmentation of melanin. Such inflammatory response facilitates skin aging. The aged skin is vulnerable to various skin infections because of reduced immunity, especially the immunity of skin cells, and the prevalence of autoimmune skin disease also increases due to increased autoantibodies in the serum. In addition, the number of Langerhans cells is smaller in the intrinsically aged skin than in the skin of young people and the number is much smaller in the photoaged skin. Accordingly, the aged skin is highly likely to develop inflammations even under weak stimulation and the inflammation triggers skin aging again. In this way, the vicious cycle goes on.